鉴定红曲菌中萘醌响应基因提高红曲色素产率

Identification of naphthoquinone-responsive gene in Monascus strain for improvement of Monascus pigments yield

由红曲菌合成的一类具有鲜明颜色的次级代谢产物被称为红曲色素,是国内销量较高的天然食用色素品种之一。前期研究发现,外源的萘醌化合物能够促进红曲菌合成红曲色素,但具体哪些基因参与这一过程仍不清楚,给后续应用带来了困难。该研究首先验证了外源萘醌化合物能够提高红色红曲菌(Monascus ruber)M7的红曲色素产率;然后采用转录组学和人工智能模型联用的方法预测了2个最有可能的萘醌响应基因:laeA和mga2;通过萘醌添加培养实验证明mga2(G蛋白β亚基)是M.ruber M7中的萘醌响应基因;最后,利用萘醌化合物白花丹醌诱导mga2基因过表达菌株,使红曲色素产率较原始菌株提高74%。该研究不仅率先发现mga2基因是红曲菌中的萘醌响应基因,并应用于提高红曲色素产率,也为其他丝状真菌中类似诱导机制的研究提供了借鉴。

Monascus pigments, which are produced by Monascus strains, exhibit bright colors. Monascus pigment is one of the natural food pigments with high sales in China. In our previous work, it was found that exogenous naphthoquinone improved the yield of Monascus pigments. However, the genes responsible for naphthoquinone response in Monascus strains are still unknow. Thus, it is hard to facilitate the practical application. In this study, it was verified that Monascus pigments yield of M. ruber M7 was promoted by the addition of exogenous naphthoquinone. Secondly, two naphthoquinone-responsive gene candidates, laeA and mga2, were revealed by a combination of transcriptomics and artificial intelligence analysis. Thirdly, mga2 gene(G protein β subunit) was identified as a naphthoquinone-responsive gene in M. ruber M7 by the direct feeding assay. Lastly, the strain M7:P;-mga2 displayed an increased Monascus pigments yield, 74% higher than that of wild type strain under the plumbagin induction condition. For the first time, this study elucidated that mga2 gene is the naphthoquinone-responsive gene in Monascus spp. This discovery was successfully employed to improve Monascus pigments yield. Furthermore, our research could be used as reference for elucidating the similar induction mechanism in other filamentous fungi.